Corona discharge voltage regulator



Sept. 28, 1954 M. o. NELSON CORONA DISCHARGE VOLTAGE REGULATOR Filed Sept. 27, 1950 INVENTOR Mnnms D. NELS UN Mu. ATTORNEY Patented Sept. 28, 1954 UNITED STATES PAT ENT OF FI'CE CORONA DISCHARGE VOLTAGE REGULATOR Morris D. Nelson, Bronx, N. Y., assignor to Radio Corporation of America, a corporation of Delaware Application September 27, 1950, Serial No. 187,121

8 Claims.

This invention relates to improvements in voltageregulating apparatus, and particularly to an improved voltage regulator of the corona discharge type.

In apparatus utilizing high unidirectional energizing voltages, and requiring that the energizing voltage be relatively constant, conventional regulating devices such as gas filled electron tubes and the like are not entirely satisfactory. In general, conventional regulating devices of this type are not adapted to operate at voltages of the order of kilovolts, and require special circuit arrangements for satisfactory use.

It is well known that if a sufilciently high voltage is impressed between two properly dimensioned and spaced conductors, the medium between the conductors will conduct current by a so-called corona discharge. Since the voltage at which this discharge takes place (hereinafter designated starting voltage) is relatively constant for a considerable range of current, it has previously been proposed to utilize a corona dis charge device as a voltage regulating apparatus (see, e. g., U. S. Patent 1,558,991, Lewrs) Since the starting voltage of such a device is relatively high, it may be used as a regulator in high voltage apparatus where more conventional regulating devices are unsatisfactory.

It is a general object of the present invention to provide an improved corona discharge voltage regulator.

A more specific object of the invention is the provision of a corona discharge voltage regulator wherein the starting voltage can be varied within reasonable limits.

In accordance with the invention, the foregoing and other related objects are attained in a corona discharge device wherein an elongated conductor is mounted in spaced relation to a conductive surface and adapted to be moved toward and away from the conductive surface by rotation of the conductor about an axis offset therefrom. In this way, the spacing between the conductor and the conductive surface can be varied to vary the voltage at which corona discharge will occur.

A more complete understanding of the invention can be had from the following description of illustrative embodiments thereof, when considered in connection with the accompanying drawing, wherein:

Figure l is a cross-section view of an adjustable corona discharge voltage regulator arranged in accordance with the invention;

Figure 2 is a cross-section view taken on the line 22 of Figure 1;

Figure 3 is a schematic diagram of a typical electrical system including a voltage regulator of the type described herein;

Figure 4 is a cross-section view of a modified form of variable voltage regulator embddying the principles of the invention; and

Figure 5 is a cross-section view of a further modified form of the invention.

Referring .to Figure 1 of the drawing, a voltage regulator embodying the principles of the invention comprises a conductive surface in the form of a cylinder 16 of brass or the like which serves as one of the conductors in a corona discharge device. A second conductor comprises an elongated conductor, such as a wire 12, embedded in one surface of a rod [4 of insulating material, such as one of the phenolic compounds (e. g., Bakelite). The rod 14 is pivotally mounted in insulating end plugs 16 at the ends of the cylinder l0, so that the rod I4 is free to rotate within the cylinder 10.

In accordance with the invention, the axis of rotation of the rod M is offset with respect to the central axis of the cylinder I 0. Since the conductor l2 extends along the periphery of the rod 14, it can be seen that the spacing between the conductor [2 and the walls of the cylinder Ill will vary as the rod I4 is rotated.

As is well known, the voltage at which the medium between two spaced conductors will conduct corona current is, in part, a function of the spacing between the two conductors. Therefore, in the apparatus shown in Figure 1, the starting voltage between the cylinder I0 and the conductor [2 can be adjusted within reasonable limits by rotation of the rod M.

The rod [4 is provided with a shoulder i8 at one end thereof, and with a removable collar I 8a at the other end, to prevent axial rod motion. If desired, a knob 20 can be placed at one end of the rod 14 to facilitate rotation thereof. Also, a cooperating pointer and scale (not shown) can be provided on the shoulder l8 and on the end plug l6, respectively, to facilitate adjustment of the starting voltage.

A conductive member or slip ring 22 in one of the end plugs 16 is adapted to contact the conductor l2 at any rotational position of the rod I4. A pair of terminals 24, 26 are connected to the cylinder 10 and to the slip ring 22, respectively, to facilitate connection of the regulating device in an electric circuit.

In Figure 3, there is shown the schematic diagram of a typical circuit arrangement utilizing a regulator of the type shown in Figures 1 and 2. In the circuit of Figure 3, a power supply 30 3 is connected to furnish unidirectional voltage through a resistor 32 to a load 34, such as a television kinescope or the like. A regulator 36, such as the regulator shown in Figures 1 and 2, is connected in shunt with the load 34.

When the power supply 30 is turned on to energize the load 34, corona discharge will take place between the elements l0, [2 in the regulator 36. For any given adjustment of the regulator, the voltage at which this discharge occurs will be relatively constant. After conduction begins, the voltage across the regulator will remain substantially constant, although the current through the regulator may vary considerably. As the load 34 draws more or less current from the power supply 30 through the resistor 32, the current through the regulator 36 will vary, while the voltage thereacross will remain substantially constant. Consequently, the voltage delivered to the load 34 will remain essentially constant regardless of changes in the current drawn by the load 34. If for any reason it becomes necessary to change the level of the voltage supplied to the load, the regulator 36 can be adjusted as previously explained to accomplish the necessary voltage change.

For example, in a television kinescope tube, the focus control often takes the form of an expensive high resistance potentiometer connected between a carefully regulated high voltage source and the final anode of the tube. With a regulator of the type shown in Figure 1, an unregulated final anode supply voltage can be used, with one regulator serving to provide a constant final anode voltage which can be adjusted for focus- In Figure 4, there is shown an alternative embodiment of the invention comprising a cylinder ID of conductive material similar to the cylinder Ill shown in Figure 1. In the Figure 4 device, the second conductor |2 comprises a rigid conductive rod, of brass or the like, mounted at its opposite ends in plugs l5 of insulating material. The plugs |5 are rotatably mounted in end plugs I6 for the cylinder ID, and the ends of the rod |2 are eccentrically located in the rotatable plugs IS. The rotatable plugs |5 are held against axial motion by a shoulder l8 and a movable collar l8a, and one of the plugs I5 is provided with a knob 26 to facilitate rotation thereof.

When the knob 20 is turned, the rod l2 will be rotated about an axis offset from the central axis of the cylinder l0, thereby moving the rod |2 closer to or further away from the walls of the cylinder l0. Contact with the rod l2 can be made in any desired manner, as by a contact ring 2| and rotating finger 25 engaging one end of the rod l2.

While the regulators shown in Figures 1, 2 and 4 are suitable for many purposes, it will be appreciated that slight changes in the regulating characteristics thereof may occur due to changes in atmospheric conditions. That is, the pressure of the air which comprises the gaseous medium for conducting the corona discharge may change, thereby altering the regulating characteristics of the device. Where more precise regulation is required, the embodiment of the invention shown in Figure 5 can be used.

In the embodiment shown in Figure 5, a metal cylinder H) has end Walls |3a, [3b of insulating material, such as glass or the like, sealed thereto. One of the end walls |3a is drawn out to provide a pivot support inside the cylinder, eccentrically disposed with respect to the axis of the cylinder.

At the other end of the cylinder, the end wall |3b is drawn out at a point off the center thereof and sealed to a smaller metal cylinder |9.

The central portion of a rigid conductor is offset from its ends 23, and the ends 23 extend into the drawn out portion of the end walls |3a, |3b to provide a pivotal mounting for the rod 2|.

t will be understood that a suitable gaseous medium, such as air or the like, is provided inside the sealed envelope formed by the cylinder l0 and the end walls |3a., l3b.

When the device shown in Fig. 5 is held in a horizontal position, the central portion of the wire 2| will fall to a position directly below the pivot supports in the end walls. When the pivot supports are at their highest point (that is, directly above the tube axis), the inner conductor will be in a position fartherest away from the walls of the cylinder Ill. On the other hand, when the device is rotated so that the pivot supports are below the cylinder axis, the central portion of the conductor 2| will drop below the supports and be in its closest position to the walls of the cylinder ID. If desired, the regulating voltage for the device can be adjusted in the manner just described, and the end cylinder I9 then can be clamped against the end 23 of the wire 2| to prevent further rotation thereof. This allows one to mount the unit in any position desired.

It will be understood that the invention is not limited to the precise embodiments illustrated and described herein. For example, in the embodiment shown in Figure 5, the position of the inner conductor 2| can be adjusted by means of a magnet if the conductor is made of magnetic material.

Since this and similar changes could be made in the apparatus shown and described, all within the scope and spirit of the invention, the foregoing is to be construed as illustrative and not in a limiting sense.

What is claimed is:

l. A corona discharge voltage regulating apparatus comprising a hollow elongated member having an electrically conductive surface, an

elongated conductor mounted in spaced relation to and substantially parallel to said conductive surface, said member and said conductor each having a central axis substantially parallel to each other, a gaseous medium between said conductive surface and said conductor, and means for rotating said conductor toward and away from said surface about an axis substantially parallel to and offset from the axes of said conductor and said member.

2. A corona discharge voltage regulating apparatus comprising a hollow cylindrical conductor, a second conductor extending through, and spaced from the walls of, said cylindrical conductor, said second conductor having a central portion offset from the ends thereof, a gaseous medium between said conductors and means pivotally mounting said second conductor ends for rotation of said second conductor within said first conductor, said mounting means having pivot points offset from the axis of said cylindrical conductor.

3. A corona discharg voltage regulating apparatus comprising a cylindrical conductor, a second conductor extending through, and spaced from the walls of, said cylindrical conductor, means mounting said second conductor for rotation thereof within said cylindrical conductor about an axis offset both from said second conductor and from the axis of said cylinder, a

gaseous medium between said conductors, means to connect said cylindrical conductor to one terminal of a voltage source, and slip-contact means engaging said second conductor for connecting said second conductor to another ter-- minal of said voltage source.

4. A corona discharge voltage regulating apparatus comprising a hollow cylindrical conductive member, plugs of insulating material closing the ends of said member, an element rotatably mounted eccentrically in each said plug, and an elongated rigid conductor, extending between said elements and having its ends eccentrically mounted in said elements, and a gaseous medium between said conductor and said conductive member.

5. A corona discharg voltage regulating apparatus comprising an elongated member having an electrically conductive surface, an elongated insulator member mounted in spaced relation to and substantially parallel to said conductive surface, a conductor extending along the surface of said insulator member, means mounting said insulator member for rotational movement thereof, and, hence, of said conductor, toward and away from said surface, and a gaseous medium between said conductive surface and said conductor.

6. In a corona discharge voltage regulating apparatus, the combination, with a cylindrical conductor, of insulating end plugs for said conductor, a second conductor, means rotatably supporting said second conductor on said end plugs within said cylindrical conductor for rotation of said second conductor about an axis offset both from said second conductor and from the axis of said cylindrical conductor, and a gaseous medium between said conductors.

7. A corona discharge voltage regulating apparatus comprising an elongated hollow conductor, a second conductor having a central portion offset from the ends thereof, insulating means sealing the ends of said hollow conductor and rotatably supporting said second conductor within said hollow conductor with said second conductor ends on a line offset from the axis of said hollow conductor, and a gaseous medium between said conductors.

8. Apparatus as defined in claim 7 wherein said insulating means includes a conductor portion insulated from said hollow conductor and contacting one of said second conductor ends.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 793,112 Wagner June 27, 1905 1,406,858 Henricks Feb. 14, 1922 2,446,170 Conley Aug. 3, 1948 2,497,272 Rainey Feb. 14, 1950 2,523,287 Friedman Sept. 26, 1950 2,562,031 Gerber July 24, 1951 

